Carbon-carbon fasteners, bolt type

Abstract

The fastening together of structural elements formed from carbon-carbon is accomplished by a fastener constructed from 2-D or 3-D carbon-carbon in the form of a high angle helical threads on one end and a countersunk head with a carbon-carbon central insert on the other end with the threaded end inserted through the carbon-carbon structural elements to be joined. A metal is painted on the threads and the shank on the fastener. A collar formed from carbon-carbon is fitted over the course threaded end of the fastener with the distal end of the threads extending therefrom. While passing a heating current through the fastener, the head and the collar of the fastener are forced together. The fastener is heated to an elevated temperature in the presence of an Oxygen gas cover which causes the powered metal to expand up to 100% binding the fastener to the carbon-carbon components, collar and insert.

What is claimed is: 
     
       1. A fastening system for joining together at least two pieces of structural carbon-carbon material comprising: a fastener, said fastener having an enlarged head for engaging a first side of one of said at least two pieces of structural carbon-carbon material to be joined and a threaded shank having a distal end extending through and beyond said at least two pieces of structural material to be joined;   a collar member with a central aperture configured to tightly slip over said distal end of said threads and press against the side of said materials to be joined remote from said head; and   a layer of a metallic powder which expands when heated in a gaseous atmosphere covering the surface of said fastener adjacent to said material to be joined and said collar whereby when the fastener is heated said metallic powder reacts with the gas of said gaseous atmosphere causing said metallic powder to expand and locking said collar to said threads and said fastener to said material which it passes through.   
     
     
       2. The invention as defined in claim 1 wherein said head additionally comprises a carbon-carbon central insert. 
     
     
       3. The invention as defined in claim 1 wherein said threads are formed of a continuous carbon fiber tow. 
     
     
       4. The invention as defined in claim 1 wherein said metallic material is Silica. 
     
     
       5. The invention as defined in claim 1 wherein said metallic powder is Titania. 
     
     
       6. The invention as defined in claim 1 wherein said gaseous atmosphere is Oxygen. 
     
     
       7. A method of joining materials of carbon-carbon structure comprising the steps of: providing a large headed elongated fastener having a shank containing high angle helical threads;   coating said fastener in the areas that come in contact with said materials to be joined and said threads with a metallic powder which expands when reacted with a specific gas;   passing the fastener through said materials and beyond with said head securing said fastener from passing entirely therethrough;   providing a collar with a central aperture and passing the distal end of said threaded portion through said aperture;   providing a force on said fastener for forcing the materials together between said head and said collar;   heating said fastener to an elevated temperature in the presence of said specific gas whereby said coating expands locking said collar to said threads and said material to said head.   
     
     
       8. The method of claim 7 wherein said threads are formed of 2-D and 3-D carbon-carbon. 
     
     
       9. The method of claim 7 wherein said coating is Silicon. 
     
     
       10. The method of claim 7 wherein said coating is selected from a group of metals consisting of Titanium, zirconium and aluminum. 
     
     
       11. The method of claim 7 wherein said specific gas is Oxygen.